Temperature Effects on Growth

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Fig. 3-3. Relative growth response of tall fescue to temperature: Y=-26.05+8.68x+0.021x2-0.0071x3; x-axis intercepts are 3 and 35°C, with an optimum at 21.25°C.

Tall fescue leaves can grow in ambient temperatures from 4 to 35°C; however, growth is optimum between 20 and 25°C (Volenec et al., 1984). These values were used to create the function displayed in Fig. 3-3, also showing temperatures corresponding to 25, 50, and 75% relative growth used as transition values between unsuitable, marginally suitable, moderately suitable, and well suited categories.

Maps shown below in Figures 3-3a, b, c, and d were created using the Internet Map Server application and the temperature tolerances shown on the temperature response function of Figure 3-3.

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Fig. 3-3a. Tall fescue suitability map for the conterminous US based on July low (13, 9, and 6 C) and high (on 31, 33, and 35 C) mean maximum temperature tolerance values.